Design for Improving Non-Linearity Error of Current Steering DAC for Biomedical Applications

Abstract

A compact current-mode Digital-to-Analog converter (DAC) suitable for neural stimulator based artificial retinal prostheses is represented in this paper .The designed DAC is binary weighted in 180nm CMOS technology with 1.8V supply voltage. In this implementation the authors have calculated for DAC having various type of switches: NMOS, PMOS switch and Transmission Gate. The implemented DAC uses lower area and power compared to unary architecture due to absence of digital decoders. The desired value of Integrated non linearity (INL) and Differential non linearity (DNL) for DAC for Artificial Retinal Prostheses are of +0.5LSB. Result obtained in this works for INL and DNL is +0.34LSB and +0.38 LSB respectively with 22mW power dissipation.